February 1991
POLICE PRACTICES:
COMPUTER AIDED DRAFTING FOR LAW ENFORCEMENT
Today, computers are used extensively in police work.
Current computer programs accommodate practically every police
function--records management, dispatching, personnel scheduling,
and supply maintenance, to name only a few applications. But,
are departments using computers to their fullest potential? In
many instances, the answer is "No!"
One area often overlooked involves installing computer-
aided drafting (CAD) software into computers. With CAD
software, the computer is used to assist with a drawing or a
design.
Most people would ask why a police department would need a
CAD program; after all, cops don't design or draw anything.
However, the value of this software package becomes obvious
considering the reoccurring need of police officers to
reconstruct crime scenes or to diagram scenes of traffic
accidents. In these types of investigations, a drawing shows
what occurred and reinforces the narrative of the report.
USES OF CAD
In a traffic accident report, the details included are most
likely proportional to the seriousness of the incident.
Usually, a minor "fender-bender" only qualifies for a few terse
lines telling what happened and a very simple diagram. On the
other hand, a multivehicle accident involving serious injuries
or fatalities dictates a more comprehensive investigation, one
that includes a detailed narrative and a scale drawing of the
accident site.
Once filed, reports on minor traffic accidents with no
injuries are often forgotten, never to be seen again. But, this
is not the case with reports on major accident investigations.
Insurance claims adjusters, lawyers, and perhaps even a judge
and jury will scrutinize these reports should cases go to
litigation. In these instances, it is important that the
diagram of the accident scene be as detailed and precise as
possible.
The same holds true for accounts of crime scenes. In their
reports, investigators must show an entire overview of the crime
scene, as well as specific areas crucial to the case. This
usually requires more than one drawing. The position of the
victim, the location of the weapon and other pertinent evidence,
and entrances and exits to the crime scene are factors in the
investigation and prosecution that must be carefully noted.
And, in many instances, the precision and detail of the report
reflect the quality of the investigation and credibility of the
investigators.
THE WORKINGS OF A CAD PROGRAM
Reconstructing an accident or crime scene requires the
investigator to show exactly what transpired, who was involved,
and the position of the objects involved. All this is
facilitated with a CAD program, because it contains pre-drawn
intersections and roadways, or buildings and rooms, onto which
information can be entered.
For example, in figure 1 (not shown in BBS version of this
article), the investigator positioned the vehicles involved in
a traffic accident, showed the direction in which the vehicles were
traveling, and indicated tire marks, visual obstructions,
traffic signs, and the scale of the diagram in feet. For a
crime scene investigation, a CAD program can be used to draw a
general view of the area and then to "zoom in" to a specific
room.
CAD programs also offer a variety of fonts and styles of
letters to show differentiations in the diagram and to give the
finished product a professional appearance. Some CAD programs
allow for letters and numbers to be indicated at any angle and
at any scale. CAD programs normally include a library of
symbols, such as vehicles, traffic signs, etc., to be used for
reconstruction purposes. And, once familiar with the program,
users can create their own symbols and store them to be
retrieved for future application.
ADVANTAGES OF CAD PROGRAMS
Using a CAD program for accident or crime scene
reconstruction offers many benefits. First, there is the
professional appearance of the diagram. A CAD program allows
the investigator to add to the diagram at any time, and the
diagram can be enlarged and reduced at any time. Once a diagram
is created, it can be resized to fit available space on a
preprinted report form. With a plotter, the same drawing can
also be made large enough for a courtroom exhibit. The finished
product is clean and free of corrections. Sloppy drawings
oftentimes reflect poorly on the quality of the investigation.
With CAD programs, there is no mess; erasures or corrections
simply do not show up on the finished product.
CAD programs prevent duplication of effort, because only
one drawing needs to be made. Then with a few keystrokes on the
computer, sections can be shown from different angles.
Many departments contract with draftsmen or engineers to
produce scale drawings. This can be quite expensive and time
consuming, which may result in a backlog of projects. Also,
additional meetings with investigators may be required to
decipher notes or measurements.
There is also the time factor to consider. Some detailed
scale drawings consume considerable workhours before they are
completed. Then, if an error is detected, the entire project
might have to be redone. With a computer and a CAD program,
alterations are generally simple and the time required to do
them is minimal. Enlargements or reductions, which would mean
additional hours at the drawing table, are produced in a matter
of seconds.
Storing or filing scale drawings also poses problems. A
large-scale drawing on a big sheet of poster board is difficult
to store since it doesn't fit in filing cabinets. As a result,
the drawing is placed wherever there is room--behind a desk, in
a storage room, next to a filing cabinet. If it is moved for
one reason or another, it may never be found. And, the more the
drawing is used in presentations, the more "worn" it becomes.
Oftentimes, additional copies of drawings need to be made
for defense attorneys and prosecutors. Large drawings are not
photo copied easily, and photographs take too long to process
and do not show details clearly. With a CAD program, making
multiple copies is a simple matter.
CONCLUSION
There are CAD programs on the market that have been
developed specifically for accident and crime scene
reconstructions. Most of the programs are inexpensive and
cost-effective, and the funds spent for them are quickly
recouped in workhours saved. With a CAD program, police
departments, regardless of size, can increase their efficiency
and expand the potential of their computer systems.
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Information for this column was submitted by Joseph E.
Badger, a retired Indiana State police sergeant.